Cable protective spring and method for fixing the cable protective spring

ABSTRACT

The present invention intends to provide a cable protection spring capable of being attached and fixed through one-touch operation without requiring an ironmongery goods or a tool for fixing.  
     In order to attain this object, according to the present invention, in the cable protection spring which is arranged in a manner that a wiring cable is passed within and through a coil spring  5  to protect the wiring cable from mechanical damage, the coil spring  5  is provided with a portion  5   a  having a diameter larger than a diameter of remaining portion thereof.

TECHNICAL FIELD

[0001] The present invention relates to a cable protection spring forprotecting a cable from mechanical damage and a method for fixing thecable protection spring to a structure.

BACKGROUND ART

[0002] In the case of disposing an electric cable in a structure such asa mechanical device or a casing, it is known to pass the electric cablewithin and through a coil spring in order to protect the electric cablefrom mechanical damage caused by, for example, stress due to strongbending, rub due to contact with a rough surface, shear due to contactwith a sharp portion. A coil spring used for such a use is generallycalled a cable protection spring. In particular, in the case ofdisposing a power cable, a signal line or a pipe for a pneumatic devicewithin the arm of an articulated robot, the cable etc. moves relativelywithin the arm in accordance with the movement of the arm. Thus, thecable protection spring for protecting the cable etc. from the damagecaused by being rubbed is indispensable.

[0003] The conventional cable protection spring has such a simple shapethat the diameter thereof is constant along its entire length, and so asaddle having an Ω-shaped section is employed in the case of fixing thecable protection spring to a structure etc.

[0004]FIG. 5 is diagrams for explaining a state where the conventionalcable protection spring is fixed to a structure etc, in which (a) is aplan view and (b) is a side view seen along a line A-A′ in (a). In thefigures, numeral 1 depicts a cable protection spring which is a coilspring formed by winding a steel wire with a fine interval. The diameterof the cable protection spring 1 is constant along its entire length.Numeral 2 depicts a structure, that is, to be more concrete, the arm ofan industrial robot etc. Numeral 3 depicts a saddle which is anironmongery goods formed by bending a rectangular steel plate into anΩ-shape. The saddles 3 are attached on the structure 2 so as to crossover the cable protection spring 1 in a manner that the cable protectionspring 1 is fastened or gripped by the Ω-shaped sectional inner side ofthe saddle and fixed to the structure 2 by means of screws 4.

[0005] However, such a conventional cable protection spring requires adedicated ironmongery goods such as a saddle for fixing the spring to astructure and further requires a tool such as a screwdriver or a wrenchin order to fix the ironmongery goods. Thus, since the number of partsand the number of assembling processes increase, there arises a problemthat a cost of the spring increases.

[0006] Further, there is another problem that skilled technique isrequired to fix the saddle. That is, if the saddle is fixed in a statethat the spring is squeezed, that is, the spring is pushed down anddeformed in an elliptic shape in its section, the spring will come outof the saddle easily when the robot moves and a tension acts on thespring. Thus, it is required to fix the saddle while paying attention soas not to deform the spring.

DISCLOSURE OF INVENTION

[0007] Accordingly, an object of the present invention is to provide acable protection spring capable of being attached and fixed throughone-touch operation without requiring an ironmongery goods or a tool forfixing. Further, an object of the present invention is to provide amethod for attaching and fixing a cable protection spring throughone-touch operation.

[0008] In order to attain the aforesaid object, the invention claimed inclaim 2 is a cable protection spring which a wiring cable is passedwithin and through a coil spring to protect the wiring cable frommechanical damage. The cable protection spring is characterized in thatthe coil spring is provided with a portion having a diameter larger thana diameter of remaining portion thereof, and a winding interval of thelarge diameter portion of the coil spring is made larger than a windinginterval of the remaining portion of the coil spring. Further, theinvention claimed in claim 4 is a method for fixing a cable protectionspring wherein the coil spring is provided with a portion having adiameter larger than a diameter of remaining portion thereof, thestructure is provided with a groove having an inlet and an outlet with asmall width and a center portion with a large width, the large diameterportion of the coil spring is compressed and pushed into the centerportion of the groove thereby to fix the coil spring within the grooveby a force acting at the center portion of the groove which is generatedat the large diameter portion of the coil spring by trying to restore toits original length. The invention claimed in claim 5 is a method forfixing a cable protection spring wherein the coil spring is providedwith a portion having a diameter smaller than a diameter of remainingportion thereof, and the structure is provided with a groove having aninlet and an outlet with a large width and a center portion with a smallwidth, the small diameter portion of the coil spring is expanded andpushed into the center portion of the groove thereby to fix the coilspring within the groove by a force acting at the center portion of thegroove which is generated at the small diameter portion of the coilspring by trying to restore to its original length.

BRIEF DESCRIPTION OF DRAWINGS

[0009]FIG. 1 is a plan view of a cable protection spring showing thefirst embodiment of the invention,

[0010]FIG. 2 is a side view of an industrial robot showing the secondembodiment of the invention,

[0011]FIG. 3 is a plan view of a cable protection spring showing thethird embodiment of the invention, and

[0012]FIG. 4 is a side view showing a state where the cable protectionspring of FIG. 3 is fixed to a structure.

[0013] FIGS. 5(a) and 5(b) are external views of a cable protectionspring showing an example of a conventional art, in which (a) is a planview and (b) is a side view seen along a line A-A′ in (a).

BEST MODE FOR CARRYING OUT THE INVENTION

[0014] Hereinafter, embodiments of the invention will be explained withreference to drawings.

[0015]FIG. 1 is a plan view of a cable protection spring showing a firstembodiment of the invention. In the figure, numeral 5 depicts a cableprotection spring. The cable protection spring 5 is a coil spring whichis formed by winding a steel wire with a fine interval so as to be in atubular shape and is provided with brim portions 5 a disposed along alongitudinal direction thereof so as to have a diameter larger than thatof the remaining portion. Each of the brim potions 5 a has the diameterlarger than that of the remaining portion and further an interval of thewinding coil is made larger, so that each of the brim portions 5 a iscompressed in its length when applied with a force in its longitudinaldirection. Hereinafter, the portion of the cable protection coil otherthan the brim portions 5 a is called a small diameter portion.

[0016] A cable to be protected which is passed within and through thecable protection spring 5 is not limited to an electric cable but may bean air pipe for a pneumatic device, a hydraulic pipe for a hydraulicdevice, a cooling water hose for cooling devices etc.

[0017]FIG. 2 is a diagram showing a second embodiment of the inventionand is a side view showing a state where the cable protection springaccording to the invention is attached to the arm of an industrialrobot.

[0018] In FIG. 2, numeral 6 depicts an industrial robot which isconfigured by a base 7, a lower arm 8 and an upper arm 9. The lower arm8 and the upper arm 9 are attached to the base 7 and the lower arm 8 soas to be able to swing freely, respectively, and are driven by anot-shown driving device. In this respect, although each of the base 7and the lower arm 8 is provided with a cover, the figure shows a statewhere the covers are removed in order to explain the internal structuresthereof. Numeral 10 depicts a cable protection spring which protects asignal line, a power line and a pipe (not shown) etc. which are directedfrom the base 7 to the upper arm 9 through the lower arm 8. Two brimportions 10 a, 10 b are provided at the cable protection spring 10.Numeral 11 depicts a groove portion provided at the base 7. The widthand the depth of each of the inlet portion 11 a and the outlet portion11 c of the groove portion 11 are made smaller than the width and thedepth of the remaining portion thereof, but is made slightly larger thanthe diameter of the small diameter portion of the cable protectionspring 10. The width and the depth of the center portion 11 b of thegroove portion 11 is made larger than the width and the depth of theremaining portion thereof, and is made slightly larger than the diameterof the brim portion 10 a of the cable protection spring 10. Further, thelength of the center portion is made shorter than that of the brimportion 10 a. Numeral 12 depicts a long groove portion provided alongalmost the entire length of the lower arm 8. The width and the depth ofeach of the inlet portion 12 a and the outlet portion 11 c of the longgroove portion 12 is made slightly larger than the diameter of the smalldiameter portion of the cable protection spring 10 but made smaller thanthe diameter of the brim portion 10 b. That is, each of the inletportion 12 a and the outlet portion 12 c has such a width and a depth ofproviding a slight allowance at the small diameter portion of the cableprotection spring 10. The width and the depth of the center portion 12 bof the long groove portion 12 is made larger than the width and thedepth of the remaining portion thereof, and is made slightly larger thanthe diameter of the brim portion 10 b of the cable protection spring 10.Further, the length of the center portion of the long groove portion ismade shorter than that of brim portion 10 b.

[0019] Next, explanation will be made as to the procedure of attachingthe cable protection spring 10 to the industrial robot 6. First, thebrim portion 10 a is compressed and shrunk in its length and insertedwithin the groove portion 11 in the compressed state. The brim portion10 a is urged against the groove portion 11 due to such a force of thebrim portion caused by trying to restore to its original length withinthe groove portion 11 and so the coil is fixed therein. Then, the cableprotection spring 10 is inserted into the inlet portion 12 a of the longgroove portion 12. Further, the brim portion 10 b is compressed andinserted into the center portion 12 c of the long groove portion 12.

[0020] In this manner, the cable protection spring 10 can be fixedthrough one-touch operation in a manner that the brim portions 10 a, 10b are inserted into the groove portion 11 and the long groove portion12, respectively.

[0021] When the aforesaid not-shown covers are attached to the base 7and the lower arm 8, the groove portion 11 and the long groove portion12 are also covered, so that the brim portions 10 a and 10 b serve as amember for preventing the groove portion 11 and the long groove portion12 from coming out. Alternatively, the groove portion and the longgroove portion may be tied with a band made of composite resin (forexample, INSULOK (trade name)) in order to prevent them from coming out.

[0022]FIG. 3 is a plan view of a cable protection spring showing a thirdembodiment of the invention. In the figure, numeral 21 depicts a cableprotection spring. The cable protection spring 21 is a coil spring whichis formed by winding a steel wire with a fine interval so as to be in atubular shape and is provided with neck portions 21 a disposed along alongitudinal direction thereof so as to have a diameter smaller thanthat of the remaining portion. Hereinafter, the portion of the cableprotection coil other than the neck portions 21 a is called a largediameter portion,

[0023]FIG. 4 is a side view showing a state where the cable protectionspring 21 is attached to a structure 22. The structure 22 is providedwith a groove portion 23 for fixing the cable protection spring 21thereto. The width and the depth of each of the inlet portion 23 a andthe outlet portion 23 c of the groove portion 23 are made larger thanthe width and the depth of the remaining portion thereof, and is madeslightly larger than the diameter of the large diameter portion of thecable protection spring 21. The width and the depth of the centerportion 23 b of the groove portion 23 is made smaller than the width andthe depth of the remaining portion thereof. Further, the width of thecenter portion is made almost equal to the diameter of the neck portion21 a of the cable protection spring 21 and the length of the centerportion is made shorter than that of neck portion 21 a.

[0024] When attaching the cable protection spring 21 to the structure22, the neck portion 21 a is extended in its length and inserted withinthe groove portion 23 in the extended state. Thus, the neck portion 21 asandwiches the center portion 23 a of the groove portion 23 by a forcecaused by trying to restore to its original length within the grooveportion 23, whereby the cable protection spring 21 is fixed to thestructure 22.

[0025] As described above, according to the invention, the cableprotection spring is provided with the brim portion having a diameterlarger than that of the remaining portion thereof, then the brim portionis pushed into the grove provided at the structure thereby to fix thecable protection spring within the groove by a reaction force of thespring. Thus, the invention can attain such a technical effect that thecable protection spring can be attached to the structure throughone-touch operation without using a tool.

Industrial Applicability

[0026] The present invention is usable for a cable protection spring forprotecting a cable from mechanical damaged and a method for fixing thecable protection spring to a structure.

1. (Deleted)
 2. (Amended) A cable protection spring which is arranged ina manner that a wiring cable is passed within and through a coil springto protect the wiring cable from mechanical damage, wherein the coilspring is provided with a portion having a diameter larger than adiameter of a remaining portion thereof, and a winding interval-of thelarge diameter portion of the coil spring is made larger than a windinginterval of the remaining portion of the coil spring.
 3. (Deleted) 4.(Amended) A method for fixing a cable protection spring, which isarranged in a manner that a wiring cable is passed within and through acoil spring to protect the wiring cable from mechanical damage, to astructure, wherein the coil spring is provided with a portion having adiameter larger than a diameter of a remaining portion thereof, thestructure is provided with a groove having an inlet and an outlet with asmall width and a center portion with a large width, the large diameterportion of the coil-spring is compressed and pushed into the centerportion of the groove thereby to fix the coil spring within the grooveby a force acting at the center portion of the groove which is generatedat the large diameter portion of the coil spring by trying to restore toan original length thereof.
 5. (Amended) A method for fixing a cableprotection spring, which is arranged in a manner that a wiring cable ispassed within and through a coil spring to protect the wiring cable frommechanical damage, to a structure, wherein the coil spring is providedwith a portion having a diameter smaller than a diameter of a remainingportion thereof, the structure is provided with a groove having an inletand an outlet with a large width and a center portion with a smallwidth, the small diameter portion of the coil spring is expanded andpushed into the center portion of the groove thereby to fix the coilspring within the groove by a force acting at the center portion of thegroove which is generated at the small diameter portion of the coilspring by trying to restore to an original length thereof.